Printing apparatus



Oct. 4, 1938. M. SCHEFFLER 2,132,086

PRINTING APPARATUS Filed Feb. 11, 1938 Patented Oct. 4, 1938 UNITEDSTATES PATENT OFFICE Application February 11, 1938, Serial No. 190,096In Germany December 28, 1935 14 Claims.

When producing prints of money value, especially bank notes, in copperplate printing or steel plate engraving one will rarely use two coloursof the same printing process and at any rate never 5 more than twocolours except for Iris copper plate printing; in exceptional cases asecond colour serves for printing so-called protection pleins which aresolid backgrounds underneath such engravings which contain the mostimportant part of the design, the background being of a different colourfrom the design. In any case, whenever a second colour in copper plateprinting is used, it serves only for delicate line work, thecolour-relief of which must not be too much squeezed broad by thesubsequent printing operation.

Such two-coloured copper plate printing is obtained by means of twoseparate printing forms, a method which however has severe drawbacks,viz. it requires a long time for drying between the :0 two printingoperations, it involves differences in register and consequently alsowaste of paper, and it prejudices the sharpness of the originalengraving of the form printed first.

Multi-colour copper plate printing in one operation is produced byinking in a printing plate after the iridescent method, i. e. bysubdividing the ink trough and filling it with different colours onenext the other which when distributed will more or less mix with eachother and which are then transmitted to the plate in stripes or streaks.The result is an iridescent play of colours which however is not alwaysof the same uniform effect.

High art prints in two or more colours in cop per plate printing andsteel engraving are obtained in such a manner that certain parts of theform which form a design by themselves and which are suflicientlydistant from each other, are carefully inked in by hand one after theother and then wiped off again.

To compensate for the impossibility of producing copper plate printingin two or more colours in such a manner that the original sharpness ofthe colour relief is preserved, one uses letterpress or plain printingin combination with one coloured copper plate printing. This too,however, owing to the necessity of damping the paper for copper plateprinting, entails considerable difference of colour register and acorresponding amount of waste paper.

Another method of producing multi-colour print by means of a singleprinting form is to ink in the form with so many form rollers as thereare colours in the picture; in this case the com- 55 position of theform rollers is so cut out that their surface corresponds with therespective colours. This method serves for printing multicolour pictureswith rough and large colour surfaces one next the other and is chieflyadopted for letterpress printing. For technical reasons, however, thismethod has never been adapted for multi-colour copper plate printing.

It is also a known method to ink in a. printing plate with differentcolours in such a manner that stencils are successively put on theprinting plate, corresponding to those parts of the design which showthe respective colour.

This method, however allows no perfect inking in because stencils cannotbe pressed so tightly against the printing form as to prevent the colourfrom getting on the form at the sides of the indentations.

This is not possible with the new invention. It refers to a printingprocess and means of producing one or multi-colour copper plate printingand steel plate engravings by means of a single printing plate, suchprints or engravings containing finest designs, patterns or guilloches,the lines of which cross each other or run one next the other, showingexact register and uninterrupted lines, also showing in all parts theoriginal sharpness of the engraving, such copper plate printing or steelengraving being produced without any wiping operation. The use of onlyone printing plate for two or more colour copper plate printing is theonly means which ensures exact and unaltered original sharpness of thevarious designs with interwoven and parallel lines.

The essential point of the invention is that for one, two or more colourprinting theprinting plate, which comprises the whole design or thewhole guilloche, is inked in, by and from the inside of a correspondingnumber of stencil cylinders which, each respectively, comprise thedifferent parts of the design or of the guilloche. The colour plates areproduced together with the originals of the printing plate after theguilloche system in one operation. The stencil. cylinders may f. i.consist of very thin steel plate or they may be hollow completecylinders and when being inked in they must fit tightly and exactly tothe printing plate; the different parts of the design are mounted,etched and (or) finished by photomechanical, chemigraphical ormechanical processes. r

The chief advantages of the new process con- 'sistapart from the exactcolour register and from the sharpness of the engravingin the unlimitednumber of colours, in the saving of ex- The means which f. i. areinvolved for rota y printing are based on the principle of a permanent,intense and positively guided development of printing plate andrespective colour stencil cylinders. This ensures perfect inking in ofall points of the engraving on the printing the line of printingplategcylinder and the stencil colour cylinder. A rotary printingmachine for producing one or more coloured copper prints according tothe invention is as an example shown on the drawing. The differentfigures represent:

Fig. 1, a schematic representation of the ma-' chine in verticalsection,

Fig. 2, an end view of a stencil cylinder,

Fig. 3, a cross section of a. stencil cylinder and cooperating parts,

Fig. 4, a perspective of the axle of a stencil cylinder-and thecooperating parts which form the ink supplying means and, r

Fig. 5, a perspective of a portion of a stencil cylinder and the :inksupplying means thereby.

The ink is by uniform pressure pressed from the ink troughs 3and 3"through the hollow axle of the stencil cylinders Band B andthrough-stationary ink feeding chambers z and z feeding ink at the lineof contact of the stencil with the plate cylinder A, and from here istransferred linewise to the printing plate. In order to prevent'the sopressed ink from flowing over laterally on to the inside of the rotatingstencil'plate or the stencil shell a and a, the ink feeding nozzle fa istightened up on both sidesandso acts like a doctor.

The cylinders B and B which carry the stencil plates are stationary andcarry rotating ring gears which mesh with the ring gears on the platecylinder A and are taken along by same. The stencil plate or the stencilshell a is put underneath or into the movable rims and is thereforepositively guided. In order to obtain a good tightening of the stencilplate and to reduce to a minimum the friction of the rotating plate orof the rotating stencil shell a lying on top of the stencil cylinders13, the latter may be provided with ball or roller bearings is embeddedinto them. The stencil tightening bar 8 must be on a level with theinside of the stencil plate and when developing on the plate cylindermust engage with the channel for fixing the plate.

2 and 2' represent wiping devices which remove small colour remnantswhich may happen to remain on the outside of the stencil plate a; I, and

I are wiping devices which clean the surface of the printing plates 0, 0from possible ink splashes and which in case the sheets contain alreadythe impression of engraved pictures also remove the partial inking in ofthe surrounding plate surface caused by the indentations of the stencilplate. The action of the wiping devices 2 and 2' is restrained only tofine wiping and is adjustable in known manner. The plate cylinder A maybe of double or quadruple the circumference of the stencil plate a andso may take double or quadruple the number of plates. The sheet is fedby the feeding cylinder D to the impression'cylinder C and after havingreceived the impression is delivered upwards printed side up. On top ofthe impression cylinder a letterpress printing device may be providedfor.

The device and the arrangement as described above for producing twocolour copper printing may be applied also for any desired number ofcolours or it may also be used only for one colour copper printing.

I claim:

1. A device for producing single and multicolour copperprints-steel-plate engraving-by means of only one printing comprising aplate cylinder carrying a printing plate upon which all parts of thedesign are inked in through stencil cylinders, the number of whichcorresponds to the number of colours, and stencil cylinders in rollingcontact with the printing plate, each stencil cylinder containing thatpart of the design which corresponds to the respective. colour.

2. A device as in claim 1, in which the stencil cylinder which servesfor inking in of the printing plate consists of highly resistantmaterial, on which the respective designs are combined byphotomechanical, chemigraphical or mechanical process and the partdesigns cleared or finished.

3. A device as in claim 1, in which the stencil cylinder which servesfor inking in of the printing plate, is a cylindrical shell of highlyresistant material, on which the respective designs are combined.

4. A device as in claim 1, having means for inking in the printing plateby distributing the ink on the inside of the stencil cylinder.

5. A device as in claim 1, including stationary cylinders, stencilsmounted for rotation about said stationary cylinders, a stationaryink.chamher in each of said stationary cylinders with a head fittingtight and doctor-like at both sides at the inside of the stencil plate,and a passage through which ink is supplied under pressure to said inkchamber.

' 6. A new device as in claim 1, including stationary cylinders withhollow axles, a stencil rotatable about each of said stationarycylinders,

a nozzle in each cylinder on the hollow axle there,"

of, said nozzle being constructed to feed ink at the inner surface ofthe corresponding stencil cylinder, and means for supplying ink to each.of said hollow axles.

'7. A device as in claim' 1, including stationary, cylinders, stencilsmounted for rotation about;

said stationary cylinders, a-stationary ink chamber in each of saidstationary cylinders, with a head-fitting tight and doctor-like at bothsides at the inside of the stencil plate, and a passage through whichink is supplied under pressure to said ink chamber includingrollerbearings on said stationary cylinders for supporting said rotatingstencils.

8. An apparatus for producing either single or multicolour undersurfaceprinting by the use of asingle printing form upon which all parts of thedesign are to be inked in, comprising a support for a printing form, arotary stencil for each colour, said stencils being mounted for; rollingcontact with said printing form and each bearing the part of the designcorresponding to its respective colour, and positive connections betweensaid printing form and said stencils for causing consists of acylindrical shell of highly resistant material.

to I

11. A device as in claim 8, including inking means arranged todistribute the ink on the inner side of the stencil.

12. A device as in claim 8, including a staaisaoss tionary cylindricalsupport for each stencil, said support bearing the stencil as a rotatingstencil cylinder, means for causing the stencil cylinders *to rotateabout their respective supports, a stationary inking device in each suchstationary-support for supplying ink to its stencil under pres sure, anda nozzle on said'inking device, fitting tight at each side againstits'stencil. I

13. A device as in claim 8, including a stationary cylindrical supportfor each stencil, said support bearing the stencil as a rotating stencilcylinde means for causing the stencil cylinders to rotate about theirrespective supports, a stationary inking device in each such stationarysupport for supplying ink to its stencil under pressure, and a nomle onsaid inking device fitting tight at each side against its stencil androller bearings between the said stationary cylindrical supports andsaid rotating stencil cylinders.

14. A device as in claim 8, including'stationary cylindrical supportseach bearing means tor supporting a stencil for rotation about thesaid'support, spaced ring gears mounted on said supports for rotationabout the respective supports, said ring gears'being constructed toreceive and hold the stencils between them and to drive the stencilspositively, and teeth on said printing form support in drivingengagement with said ring 7 gears. I

MAX FRIEDRICH SCHEFFLER.

